syslinux_already_installed function will be used in both extlinux and
syslinux for checking if the boot sector has either the string
"SYSLINUX" or "EXTLINUX" in the OEMID field.

Signed-off-by: Paulo Alcantara <pcacjr@gmail.com>

1. Make sure extents are strictly less than 64K in size
2. Make sure extents do not cross 64K boundaries

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

gcc 4.6 warns on variables set but not used, so remove them.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

Put a magic signature at the end of the boot sector, and a backpointer
to the code that contains the pointer to the main code extent.  This
is useful for integrity-checking tools, and could help the installer
in the future.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

In 'libinstaller/syslxopt.c' on line 71 the "s" (undercast) is missing in:

   const char short_options[] = "t:fid:UuzS:H:rvho:OM:ma";

Adding the 's' there seems to solve our problem.

Remove a lengthy warning message which cause the actual command
reference to overflow a 24-line screen.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

Fix fatal warnings in syslxopt.c partly due to legal but non-idiomatic
use of switch().  Since the only purpose was to conditionalize single
output statements, just do it explicitly.

In addition, since they are conditional messages, there is no need to
explain when they apply.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

Gert Hulselmans noticed this.

We will produce an error message if a user attempts
to use an option we don't implement.

Signed-off-by: Shao Miller <shao.miller@yrdsb.edu.on.ca>